代码中很多地方，都写了注释说明~基本不需要怎么解释了~
package net.micode.fileexplorer.util;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FilenameFilter;
import java.io.IOException;
import java.text.DateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.HashSet;
import net.micode.fileexplorer.FileViewActivity;
import net.micode.fileexplorer.GlobalConsts;
import net.micode.fileexplorer.R;
import net.micode.fileexplorer.model.FavoriteItem;
import net.micode.fileexplorer.model.FileInfo;
import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.content.pm.ApplicationInfo;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.graphics.drawable.Drawable;
import android.os.Environment;
import android.util.Log;
import android.view.ActionMode;
import android.view.View;
import android.widget.TextView;
/**工具类，包含了很多通用的工具方法，被项目中的很多类调用。*/
public class Util {
//这个文件夹里面存储的内容是app2sd产生的文件夹，也就是是你手机上所有安装到SD卡的应用程序的缓存文件夹。
//androidsecure文件夹可以删除吗？
//如果删除之后，软件不能正常使用，和系统没有关系。
//删的话除了会可能导致移动至sd卡的程序损坏，数据丢失，并不会造成什么严重后果。只要把移动到sd卡的损坏程序卸载，重装，手机就完全没有损伤，文件夹也会在再次app2sd时自动重建的。
private static String ANDROID_SECURE = "/mnt/sdcard/.android_secure";
//android.util.Log.log第1个参数，用到“tag”，和log4j中Logger.getLogger(getClass())用法不太一样
private static final String LOG_TAG = "Util";
//获得SD卡的存储状态，“mounted”表示已经就绪
public static boolean isSDCardReady() {
return Environment.getExternalStorageState().equals(
Environment.MEDIA_MOUNTED);
}
// if path1 contains path2
public static boolean containsPath(String path1, String path2) {
String path = path2;
while (path != null) {
if (path.equalsIgnoreCase(path1))
return true;
if (path.equals(GlobalConsts.ROOT_PATH))
break;
path = new File(path).getParent();
}
return false;
}
//2个路径相加的时候，是否需要加上文件分隔符
public static String makePath(String path1, String path2) {
if (path1.endsWith(File.separator))
return path1 + path2;
return path1 + File.separator + path2;
}
//获得SD卡的存储目录
public static String getSdDirectory() {
return Environment.getExternalStorageDirectory().getPath();
}
//判断1个文件是否为“普通文件”，ANDROID_SECURE下的文件都不是普通的
public static boolean isNormalFile(String fullName) {
return !fullName.equals(ANDROID_SECURE);
}
//根据文件路径，获得Java文件File，再包装成FileInfo
public static FileInfo GetFileInfo(String filePath) {
File lFile = new File(filePath);
if (!lFile.exists())
return null;
FileInfo lFileInfo = new FileInfo();
lFileInfo.canRead = lFile.canRead();
lFileInfo.canWrite = lFile.canWrite();
lFileInfo.isHidden = lFile.isHidden();
lFileInfo.fileName = Util.getNameFromFilepath(filePath);
lFileInfo.ModifiedDate = lFile.lastModified();
lFileInfo.IsDir = lFile.isDirectory();
lFileInfo.filePath = filePath;
lFileInfo.fileSize = lFile.length();
return lFileInfo;
}
//根据File对象，和FilenameFilter等选项，获得包装的FileInfo
//需要注意多少，如果File是个目录，Count就是当前目录下的文件的个数。如果是普通文件，就计算文件大小。
//这个时候，我们知道Count字段的含义了
public static FileInfo GetFileInfo(File f, FilenameFilter filter,
boolean showHidden) {
FileInfo lFileInfo = new FileInfo();
String filePath = f.getPath();
File lFile = new File(filePath);
lFileInfo.canRead = lFile.canRead();
lFileInfo.canWrite = lFile.canWrite();
lFileInfo.isHidden = lFile.isHidden();
lFileInfo.fileName = f.getName();
lFileInfo.ModifiedDate = lFile.lastModified();
lFileInfo.IsDir = lFile.isDirectory();
lFileInfo.filePath = filePath;
if (lFileInfo.IsDir) {
int lCount = 0;
File[] files = lFile.listFiles(filter);
// null means we cannot access this dir
if (files == null) {
return null;
}
for (File child : files) {
if ((!child.isHidden() || showHidden)
&& Util.isNormalFile(child.getAbsolutePath())) {
lCount++;
}
}
lFileInfo.Count = lCount;
} else {
lFileInfo.fileSize = lFile.length();
}
return lFileInfo;
}
/*
* 采用了新的办法获取APK图标，之前的失败是因为android中存在的一个BUG,通过 appInfo.publicSourceDir =
* apkPath;来修正这个问题，详情参见:
* http://code.google.com/p/android/issues/detail?id=9151
*/
public static Drawable getApkIcon(Context context, String apkPath) {
//Android系统为我们提供了很多服务管理类，包括ActivityManager、PowerManager(电源管理)、AudioManager(音频管理)。
//PackageManager主要是管理应用程序包，通过它就可以获取应用程序信息
PackageManager pm = context.getPackageManager();
PackageInfo info = pm.getPackageArchiveInfo(apkPath,
PackageManager.GET_ACTIVITIES);
if (info != null) {
ApplicationInfo appInfo = info.applicationInfo;
appInfo.sourceDir = apkPath;
appInfo.publicSourceDir = apkPath;
try {
return appInfo.loadIcon(pm);
} catch (OutOfMemoryError e) {
Log.e(LOG_TAG, e.toString());
}
}
return null;
}
//获得文件的扩展名
public static String getExtFromFilename(String filename) {
int dotPosition = filename.lastIndexOf('.');
if (dotPosition != -1) {
return filename.substring(dotPosition + 1, filename.length());
}
return "";
}
//获得去掉“文件后缀”的文件名字，比如“C:/a/b/c.png”，输出“C:/a/b/c”
public static String getNameFromFilename(String filename) {
int dotPosition = filename.lastIndexOf('.');
if (dotPosition != -1) {
return filename.substring(0, dotPosition);
}
return "";
}
//从文件路径中，获得路径
public static String getPathFromFilepath(String filepath) {
int pos = filepath.lastIndexOf('/');
if (pos != -1) {
return filepath.substring(0, pos);
}
return "";
}
//从文件路径中，获得文件名（带后缀，如果有）
public static String getNameFromFilepath(String filepath) {
int pos = filepath.lastIndexOf('/');
if (pos != -1) {
return filepath.substring(pos + 1);
}
return "";
}
// return new file path if successful, or return null
public static String copyFile(String src, String dest) {
File file = new File(src);
if (!file.exists() || file.isDirectory()) {
Log.v(LOG_TAG, "copyFile: file not exist or is directory, " + src);
return null;
}
FileInputStream fi = null;
FileOutputStream fo = null;
try {
fi = new FileInputStream(file);
File destPlace = new File(dest);
if (!destPlace.exists()) {
if (!destPlace.mkdirs())
return null;
}
String destPath = Util.makePath(dest, file.getName());
File destFile = new File(destPath);
int i = 1;
while (destFile.exists()) {
String destName = Util.getNameFromFilename(file.getName())
+ " " + i++ + "."
+ Util.getExtFromFilename(file.getName());
destPath = Util.makePath(dest, destName);
destFile = new File(destPath);
}
if (!destFile.createNewFile())
return null;
fo = new FileOutputStream(destFile);
int count = 102400;
byte[] buffer = new byte[count];
int read = 0;
while ((read = fi.read(buffer, 0, count)) != -1) {
fo.write(buffer, 0, read);
}
// TODO: set access privilege
return destPath;
} catch (FileNotFoundException e) {
Log.e(LOG_TAG, "copyFile: file not found, " + src);
e.printStackTrace();
} catch (IOException e) {
Log.e(LOG_TAG, "copyFile: " + e.toString());
} finally {
try {
if (fi != null)
fi.close();
if (fo != null)
fo.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return null;
}
// does not include sd card folder
private static String[] SysFileDirs = new String[] { "miren_browser/imagecaches" };
//判断一个文件是否需要显示，根据Setting中的设置。特别说明：某个系统文件目录，不显示。
public static boolean shouldShowFile(String path) {
return shouldShowFile(new File(path));
}
//判断一个文件是否需要显示，根据Setting中的设置。特别说明：某个系统文件目录，不显示。
public static boolean shouldShowFile(File file) {
boolean show = Settings.instance().getShowDotAndHiddenFiles();
if (show)
return true;
if (file.isHidden())
return false;
if (file.getName().startsWith("."))
return false;
String sdFolder = getSdDirectory();
for (String s : SysFileDirs) {
if (file.getPath().startsWith(makePath(sdFolder, s)))
return false;
}
return true;
}
//根据上下文对象Context，获得默认的收藏集合
public static ArrayList<FavoriteItem> getDefaultFavorites(Context context) {
ArrayList<FavoriteItem> list = new ArrayList<FavoriteItem>();
list.add(new FavoriteItem(context.getString(R.string.favorite_photo),
makePath(getSdDirectory(), "DCIM/Camera")));
list.add(new FavoriteItem(context.getString(R.string.favorite_sdcard),
getSdDirectory()));
// list.add(new FavoriteItem(context.getString(R.string.favorite_root),
// getSdDirectory()));
list.add(new FavoriteItem(context
.getString(R.string.favorite_screen_cap), makePath(
getSdDirectory(), "MIUI/screen_cap")));
list.add(new FavoriteItem(
context.getString(R.string.favorite_ringtone), makePath(
getSdDirectory(), "MIUI/ringtone")));
return list;
}
//向View中的某个TextView设置文本
public static boolean setText(View view, int id, String text) {
TextView textView = (TextView) view.findViewById(id);
if (textView == null)
return false;
textView.setText(text);
return true;
}
//向View中的某个TextView设置文本
public static boolean setText(View view, int id, int text) {
TextView textView = (TextView) view.findViewById(id);
if (textView == null)
return false;
textView.setText(text);
return true;
}
// comma separated number
public static String convertNumber(long number) {
return String.format("%,d", number);
}
// storage, G M K B
public static String convertStorage(long size) {
long kb = 1024;
long mb = kb * 1024;
long gb = mb * 1024;
if (size >= gb) {
return String.format("%.1f GB", (float) size / gb);
} else if (size >= mb) {
float f = (float) size / mb;
return String.format(f > 100 ? "%.0f MB" : "%.1f MB", f);
} else if (size >= kb) {
float f = (float) size / kb;
return String.format(f > 100 ? "%.0f KB" : "%.1f KB", f);
} else
return String.format("%d B", size);
}
public static class SDCardInfo {
public long total;
public long free;
}
//获得SD卡的各种信息，总容量大小和剩余容量大小等
public static SDCardInfo getSDCardInfo() {
String sDcString = android.os.Environment.getExternalStorageState();
if (sDcString.equals(android.os.Environment.MEDIA_MOUNTED)) {
File pathFile = android.os.Environment
.getExternalStorageDirectory();
try {
android.os.StatFs statfs = new android.os.StatFs(
pathFile.getPath());
// 获取SDCard上BLOCK总数
long nTotalBlocks = statfs.getBlockCount();
// 获取SDCard上每个block的SIZE
long nBlocSize = statfs.getBlockSize();
// 获取可供程序使用的Block的数量
long nAvailaBlock = statfs.getAvailableBlocks();
// 获取剩下的所有Block的数量(包括预留的一般程序无法使用的块)
long nFreeBlock = statfs.getFreeBlocks();
SDCardInfo info = new SDCardInfo();
// 计算SDCard 总容量大小MB
info.total = nTotalBlocks * nBlocSize;
// 计算 SDCard 剩余大小MB
info.free = nAvailaBlock * nBlocSize;
return info;
} catch (IllegalArgumentException e) {
Log.e(LOG_TAG, e.toString());
}
}
return null;
}
//显示一条系统通知
public static void showNotification(Context context, Intent intent,
String title, String body, int drawableId) {
NotificationManager manager = (NotificationManager) context
.getSystemService(Context.NOTIFICATION_SERVICE);
Notification notification = new Notification(drawableId, body,
System.currentTimeMillis());
notification.flags = Notification.FLAG_AUTO_CANCEL;
notification.defaults = Notification.DEFAULT_SOUND;
if (intent == null) {
// FIXEME: category tab is disabled
intent = new Intent(context, FileViewActivity.class);
}
PendingIntent contentIntent = PendingIntent.getActivity(context, 0,
intent, PendingIntent.FLAG_ONE_SHOT);
notification.setLatestEventInfo(context, title, body, contentIntent);
manager.notify(drawableId, notification);
}
//格式化毫秒格式的时间
public static String formatDateString(Context context, long time) {
DateFormat dateFormat = android.text.format.DateFormat
.getDateFormat(context);
DateFormat timeFormat = android.text.format.DateFormat
.getTimeFormat(context);
Date date = new Date(time);
return dateFormat.format(date) + " " + timeFormat.format(date);
}
public static void updateActionModeTitle(ActionMode mode, Context context,
int selectedNum) {
if (mode != null) {
mode.setTitle(context.getString(R.string.multi_select_title,
selectedNum));
if (selectedNum == 0) {
mode.finish();
}
}
}
//MimeType
public static HashSet<String> sDocMimeTypesSet = new HashSet<String>() {
{
add("text/plain");
add("text/plain");
add("application/pdf");
add("application/msword");
add("application/vnd.ms-excel");
add("application/vnd.ms-excel");
}
};
public static String sZipFileMimeType = "application/zip";
public static int CATEGORY_TAB_INDEX = 0;
public static int SDCARD_TAB_INDEX = 1;
}遇到一个奇怪的问题，为了验证某个函数，写了个main函数执行，结果发生了奇葩事项~
在Java环境下的工程中执行以下代码，正常输出。
public class Test {
public static void main(String[] args) {
System.out.println(getNameFromFilename("C:/a/b/c.png"));
}
public static String getNameFromFilename(String filename) {
int dotPosition = filename.lastIndexOf('.');
if (dotPosition != -1) {
return filename.substring(0, dotPosition);
}
return "";
}
}打印“C:/a/b/c”
在Android环境下的工程中，竟然直接把JVM搞崩溃了，不明所以啊~
Invalid layout of java.lang.String at value
#
# A fatal error has been detected by the Java Runtime Environment:
#
# Internal Error (javaClasses.cpp:129), pid=8236, tid=3188
# fatal error: Invalid layout of preloaded class
#
# JRE version: 7.0_17-b02
# Java VM: Java HotSpot(TM) 64-Bit Server VM (23.7-b01 mixed mode windows-amd64 compressed oops)
# Failed to write core dump. Minidumps are not enabled by default on client versions of Windows
#
# An error report file with more information is saved as:
# J:AndroidCenterMiCodeFileExplorerhs_err_pid8236.log
#
# If you would like to submit a bug report, please visit:
# http://bugreport.sun.com/bugreport/crash.jsp
#